The present invention relates to a method of and an arrangement for filling liquids under counterpressure into containers, such as bottles, cans and the like.
Methods and arrangements of the above-mentioned general type are known in the art. In accordance with known methods and arrangements, a container to be filled is first evacuated, then advantageously through a gas pipe it is put under pressure, and subsequently the liquid is supplied into the container, whereas after termination of the filling step an unloading of the container pressure to atmospheric pressure takes place.
In the known methods the classic pre-evacuation takes place with the aid of a return gas pipe. The fluid is filled, after evacuation of the bottles and pretensioning of its interior to the pressure acting in a filling machine tank, by automatic opening of the filling valve. As long as the liquid filled in the bottle reaches the opening of the return gas pipe, the latter is automatically closed by the liquid level so that a further gas exchange through this return air or return gas opening no longer takes place. Thereby, the filling step ends. Subsequently, the unloading of the negative pressure formed in the bottles, relative to the atmosphere takes place, and special passages are provided which communicate the interior of the bottle above the liquid level with the outside air. During the filling step and reaching the return gas pipe, a flow portion of liquid travels into the return gas pipe. Simultaneously, in the space above the liquid level there is an unavoidable surface foam, particularly in the event of CO.sub.2 -containing drinks, and during the unloading step certain liquid residues break outwardly. Moreover, the fluid portion inside the return gas pipe is disturbing with a certain limit during the subsequent evacuation and pretensioning of a subsequent bottle.